utils/checkpackagelib: CommentsMenusPackagesOrder: initialize 'menu_of_packages' array

'source' without a previous 'menu' is common in package/Config.in in
br2-externals.

Signed-off-by: Jerzy Grzegorek <jerzy.m.grzegorek@gmail.com>
Cc: Ricardo Martincoski <ricardo.martincoski@gmail.com>
Reviewed-by: Ricardo Martincoski <ricardo.martincoski@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

utils/checkpackagelib/lib_config.py

@@ -63,7 +63,7 @@ class AttributesOrder(_CheckFunction):
 class CommentsMenusPackagesOrder(_CheckFunction):
     def before(self):
         self.level = 0
-        self.menu_of_packages = [""]
+        self.menu_of_packages = ["The top level menu"]
         self.new_package = ""
         self.package = [""]
         self.print_package_warning = [True]